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Further reduce use of const char* in <wtf/DateMath.h>
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https://bugs.webkit.org/show_bug.cgi?id=273534

Reviewed by Per Arne Vollan.

Further reduce use of const char* in <wtf/DateMath.h> by leveraging std::span.

* Source/JavaScriptCore/runtime/JSDateMath.cpp:
(JSC::DateCache::parseDate):
* Source/WTF/wtf/DateMath.cpp:
(WTF::parseES5DatePortion):
(WTF::parseES5TimePortion):
(WTF::parseES5Date):
(WTF::parseES5DateFromNullTerminatedCharacters): Deleted.
* Source/WTF/wtf/DateMath.h:

Canonical link: https://commits.webkit.org/278265@main
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@cdumez
cdumez committed May 2, 2024
1 parent bafd895 commit 0601607
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Showing 3 changed files with 103 additions and 115 deletions.
8 changes: 4 additions & 4 deletions Source/JavaScriptCore/runtime/JSDateMath.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -451,19 +451,19 @@ double DateCache::parseDate(JSGlobalObject* globalObject, VM& vm, const String&
return std::numeric_limits<double>::quiet_NaN();
}

auto parseDateImpl = [this] (const CString& dateString) {
auto parseDateImpl = [this] (auto dateString) {
bool isLocalTime;
double value = WTF::parseES5DateFromNullTerminatedCharacters(dateString.data(), isLocalTime);
double value = WTF::parseES5Date(dateString, isLocalTime);
if (std::isnan(value))
value = WTF::parseDate(dateString.span(), isLocalTime);
value = WTF::parseDate(dateString, isLocalTime);

if (isLocalTime && std::isfinite(value))
value -= localTimeOffset(static_cast<int64_t>(value), WTF::LocalTime).offset;

return value;
};

double value = parseDateImpl(expectedString.value());
double value = parseDateImpl(expectedString.value().span());
m_cachedDateString = date;
m_cachedDateStringValue = value;
return value;
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208 changes: 98 additions & 110 deletions Source/WTF/wtf/DateMath.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -453,17 +453,6 @@ static int findMonth(std::span<const LChar> monthStr)
return -1;
}

// FIXME: Port call sites to the overload taking in a span and remove.
static bool parseInt(const char* string, char** stopPosition, int base, int* result)
{
long longResult = strtol(string, stopPosition, base);
// Avoid the use of errno as it is not available on Windows CE
if (string == *stopPosition || longResult <= std::numeric_limits<int>::min() || longResult >= std::numeric_limits<int>::max())
return false;
*result = longResult;
return true;
}

static bool parseInt(std::span<const LChar>& string, int base, int* result)
{
char* stopPosition;
Expand All @@ -476,16 +465,6 @@ static bool parseInt(std::span<const LChar>& string, int base, int* result)
return true;
}

// FIXME: Port call sites to the overload taking in a span and remove.
static bool parseLong(const char* string, char** stopPosition, int base, long* result)
{
*result = strtol(string, stopPosition, base);
// Avoid the use of errno as it is not available on Windows CE
if (string == *stopPosition || *result == std::numeric_limits<long>::min() || *result == std::numeric_limits<long>::max())
return false;
return true;
}

static bool parseLong(std::span<const LChar>& string, int base, long* result)
{
char* stopPosition;
Expand All @@ -500,162 +479,172 @@ static bool parseLong(std::span<const LChar>& string, int base, long* result)
// Parses a date with the format YYYY[-MM[-DD]].
// Year parsing is lenient, allows any number of digits, and +/-.
// Returns 0 if a parse error occurs, else returns the end of the parsed portion of the string.
static char* parseES5DatePortion(const char* currentPosition, int& year, long& month, long& day)
static bool parseES5DatePortion(std::span<const LChar>& currentPosition, int& year, long& month, long& day)
{
char* postParsePosition;

// This is a bit more lenient on the year string than ES5 specifies:
// instead of restricting to 4 digits (or 6 digits with mandatory +/-),
// it accepts any integer value. Consider this an implementation fallback.
bool hasNegativeYear = *currentPosition == '-';
if (!parseInt(currentPosition, &postParsePosition, 10, &year))
return nullptr;
bool hasNegativeYear = !currentPosition.empty() && currentPosition.front() == '-';
if (!parseInt(currentPosition, 10, &year))
return false;
if (!year && hasNegativeYear)
return nullptr;
return false;

// Check for presence of -MM portion.
if (*postParsePosition != '-')
return postParsePosition;
currentPosition = postParsePosition + 1;
if (currentPosition.empty() || currentPosition.front() != '-')
return true;
currentPosition = currentPosition.subspan(1);

if (!isASCIIDigit(*currentPosition))
return nullptr;
if (!parseLong(currentPosition, &postParsePosition, 10, &month))
return nullptr;
if ((postParsePosition - currentPosition) != 2)
return nullptr;
if (currentPosition.empty() || !isASCIIDigit(currentPosition.front()))
return false;
auto postParsePosition = currentPosition;
if (!parseLong(postParsePosition, 10, &month))
return false;
if ((postParsePosition.data() - currentPosition.data()) != 2)
return false;
currentPosition = postParsePosition;

// Check for presence of -DD portion.
if (*postParsePosition != '-')
return postParsePosition;
currentPosition = postParsePosition + 1;
if (currentPosition.empty() || currentPosition.front() != '-')
return true;
currentPosition = currentPosition.subspan(1);

if (!isASCIIDigit(*currentPosition))
return nullptr;
if (!parseLong(currentPosition, &postParsePosition, 10, &day))
return nullptr;
if ((postParsePosition - currentPosition) != 2)
return nullptr;
return postParsePosition;
if (currentPosition.empty() || !isASCIIDigit(currentPosition.front()))
return false;
postParsePosition = currentPosition;
if (!parseLong(postParsePosition, 10, &day))
return false;
if ((postParsePosition.data() - currentPosition.data()) != 2)
return false;
currentPosition = postParsePosition;
return true;
}

// Parses a time with the format HH:mm[:ss[.sss]][Z|(+|-)(00:00|0000|00)].
// Fractional seconds parsing is lenient, allows any number of digits.
// Returns 0 if a parse error occurs, else returns the end of the parsed portion of the string.
static char* parseES5TimePortion(char* currentPosition, long& hours, long& minutes, long& seconds, double& milliseconds, bool& isLocalTime, long& timeZoneSeconds)
static bool parseES5TimePortion(std::span<const LChar>& currentPosition, long& hours, long& minutes, long& seconds, double& milliseconds, bool& isLocalTime, long& timeZoneSeconds)
{
isLocalTime = false;

char* postParsePosition;
if (!isASCIIDigit(*currentPosition))
return nullptr;
if (!parseLong(currentPosition, &postParsePosition, 10, &hours))
return nullptr;
if (*postParsePosition != ':' || (postParsePosition - currentPosition) != 2)
return nullptr;
currentPosition = postParsePosition + 1;
if (currentPosition.empty() || !isASCIIDigit(currentPosition.front()))
return false;

auto postParsePosition = currentPosition;
if (!parseLong(postParsePosition, 10, &hours))
return false;
if (postParsePosition.empty() || postParsePosition.front() != ':' || (postParsePosition.data() - currentPosition.data()) != 2)
return false;
currentPosition = postParsePosition.subspan(1);

if (!isASCIIDigit(*currentPosition))
return nullptr;
if (!parseLong(currentPosition, &postParsePosition, 10, &minutes))
return nullptr;
if ((postParsePosition - currentPosition) != 2)
return nullptr;
if (currentPosition.empty() || !isASCIIDigit(currentPosition.front()))
return false;
postParsePosition = currentPosition;
if (!parseLong(postParsePosition, 10, &minutes))
return false;
if ((postParsePosition.data() - currentPosition.data()) != 2)
return false;
currentPosition = postParsePosition;

// Seconds are optional.
if (*currentPosition == ':') {
++currentPosition;
if (!currentPosition.empty() && currentPosition.front() == ':') {
currentPosition = currentPosition.subspan(1);

if (!isASCIIDigit(*currentPosition))
return nullptr;
if (!parseLong(currentPosition, &postParsePosition, 10, &seconds))
return nullptr;
if ((postParsePosition - currentPosition) != 2)
return nullptr;
if (*postParsePosition == '.') {
currentPosition = postParsePosition + 1;
if (currentPosition.empty() || !isASCIIDigit(currentPosition.front()))
return false;
postParsePosition = currentPosition;
if (!parseLong(postParsePosition, 10, &seconds))
return false;
if ((postParsePosition.data() - currentPosition.data()) != 2)
return false;
if (!postParsePosition.empty() && postParsePosition.front() == '.') {
currentPosition = postParsePosition.subspan(1);

// In ECMA-262-5 it's a bit unclear if '.' can be present without milliseconds, but
// a reasonable interpretation guided by the given examples and RFC 3339 says "no".
// We check the next character to avoid reading +/- timezone hours after an invalid decimal.
if (!isASCIIDigit(*currentPosition))
return nullptr;
if (currentPosition.empty() || !isASCIIDigit(currentPosition.front()))
return false;

// We are more lenient than ES5 by accepting more or less than 3 fraction digits.
long fracSeconds;
if (!parseLong(currentPosition, &postParsePosition, 10, &fracSeconds))
return nullptr;
postParsePosition = currentPosition;
if (!parseLong(postParsePosition, 10, &fracSeconds))
return false;

long numFracDigits = postParsePosition - currentPosition;
long numFracDigits = postParsePosition.data() - currentPosition.data();
milliseconds = fracSeconds * pow(10.0, static_cast<double>(-numFracDigits + 3));
}
currentPosition = postParsePosition;
}

if (*currentPosition == 'Z')
return currentPosition + 1;
if (!currentPosition.empty() && currentPosition.front() == 'Z') {
currentPosition = currentPosition.subspan(1);
return true;
}

// Parse (+|-)(00:00|0000|00).
bool tzNegative;
if (*currentPosition == '-')
if (!currentPosition.empty() && currentPosition.front() == '-')
tzNegative = true;
else if (*currentPosition == '+')
else if (!currentPosition.empty() && currentPosition.front() == '+')
tzNegative = false;
else {
isLocalTime = true;
return currentPosition;
return true;
}
++currentPosition;
currentPosition = currentPosition.subspan(1);

long tzHours = 0;
long tzHoursAbs = 0;
long tzMinutes = 0;

if (!isASCIIDigit(*currentPosition))
return nullptr;
if (!parseLong(currentPosition, &postParsePosition, 10, &tzHours))
return nullptr;
if (*postParsePosition != ':') {
if ((postParsePosition - currentPosition) == 2) {
if (currentPosition.empty() || !isASCIIDigit(currentPosition.front()))
return false;
postParsePosition = currentPosition;
if (!parseLong(postParsePosition, 10, &tzHours))
return false;
if (postParsePosition.empty() || postParsePosition.front() != ':') {
if ((postParsePosition.data() - currentPosition.data()) == 2) {
// "00" case.
tzHoursAbs = labs(tzHours);
} else if ((postParsePosition - currentPosition) == 4) {
} else if ((postParsePosition.data() - currentPosition.data()) == 4) {
// "0000" case.
tzHoursAbs = labs(tzHours);
tzMinutes = tzHoursAbs % 100;
tzHoursAbs = tzHoursAbs / 100;
} else
return nullptr;
return false;
} else {
// "00:00" case.
if ((postParsePosition - currentPosition) != 2)
return nullptr;
if ((postParsePosition.data() - currentPosition.data()) != 2)
return false;
tzHoursAbs = labs(tzHours);
currentPosition = postParsePosition + 1; // Skip ":".
currentPosition = postParsePosition.subspan(1); // Skip ":".

if (!isASCIIDigit(*currentPosition))
return nullptr;
if (!parseLong(currentPosition, &postParsePosition, 10, &tzMinutes))
return nullptr;
if ((postParsePosition - currentPosition) != 2)
return nullptr;
if (currentPosition.empty() || !isASCIIDigit(currentPosition.front()))
return false;
postParsePosition = currentPosition;
if (!parseLong(postParsePosition, 10, &tzMinutes))
return false;
if ((postParsePosition.data() - currentPosition.data()) != 2)
return false;
}
currentPosition = postParsePosition;

if (tzHoursAbs > 24)
return nullptr;
return false;
if (tzMinutes < 0 || tzMinutes > 59)
return nullptr;
return false;

timeZoneSeconds = 60 * (tzMinutes + (60 * tzHoursAbs));
if (tzNegative)
timeZoneSeconds = -timeZoneSeconds;

return currentPosition;
return true;
}

double parseES5DateFromNullTerminatedCharacters(const char* dateString, bool& isLocalTime)
double parseES5Date(std::span<const LChar> dateString, bool& isLocalTime)
{
isLocalTime = false;

Expand All @@ -676,19 +665,18 @@ double parseES5DateFromNullTerminatedCharacters(const char* dateString, bool& is
long timeZoneSeconds = 0;

// Parse the date YYYY[-MM[-DD]]
char* currentPosition = parseES5DatePortion(dateString, year, month, day);
if (!currentPosition)
if (!parseES5DatePortion(dateString, year, month, day))
return std::numeric_limits<double>::quiet_NaN();
// Look for a time portion.
// Note: As of ES2016, when a UTC offset is missing, date-time forms are local time while date-only forms are UTC.
if (*currentPosition == 'T' || *currentPosition == 't' || *currentPosition == ' ') {
if (!dateString.empty() && (dateString.front() == 'T' || dateString.front() == 't' || dateString.front() == ' ')) {
dateString = dateString.subspan(1);
// Parse the time HH:mm[:ss[.sss]][Z|(+|-)(00:00|0000|00)]
currentPosition = parseES5TimePortion(currentPosition + 1, hours, minutes, seconds, milliseconds, isLocalTime, timeZoneSeconds);
if (!currentPosition)
if (!parseES5TimePortion(dateString, hours, minutes, seconds, milliseconds, isLocalTime, timeZoneSeconds))
return std::numeric_limits<double>::quiet_NaN();
}
// Check that we have parsed all characters in the string.
if (*currentPosition)
if (!dateString.empty())
return std::numeric_limits<double>::quiet_NaN();

// A few of these checks could be done inline above, but since many of them are interrelated
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2 changes: 1 addition & 1 deletion Source/WTF/wtf/DateMath.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -77,7 +77,7 @@ void initializeDates();
int equivalentYearForDST(int year);

// Not really math related, but this is currently the only shared place to put these.
WTF_EXPORT_PRIVATE double parseES5DateFromNullTerminatedCharacters(const char* dateString, bool& isLocalTime);
WTF_EXPORT_PRIVATE double parseES5Date(std::span<const LChar> dateString, bool& isLocalTime);
WTF_EXPORT_PRIVATE double parseDate(std::span<const LChar> dateString);
WTF_EXPORT_PRIVATE double parseDate(std::span<const LChar> dateString, bool& isLocalTime);
// dayOfWeek: [0, 6] 0 being Monday, day: [1, 31], month: [0, 11], year: ex: 2011, hours: [0, 23], minutes: [0, 59], seconds: [0, 59], utcOffset: [-720,720].
Expand Down

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